The human skin is the largest sense organ. Due to the presence of an extensive network of nerve fibers ending in the surface layers of the skin with sensitive receptors, it provides the perception of various types of sensitivity. On average, one square centimeter of human skin has 100–200 pain receptors, 12–15 cold receptors, 1–2 heat receptors, and about 25 tactile receptors. This proves the importance of pain as a protective reaction to the aggressive impact of the environment on a person.